Edwaed w



(No Model.) Y

B. W BRIGGS 82: J. D. WALTON.

PUNCH. N0. 295,227. Patented Mar. 18, 1884.

Wit. msse s iiiurrrio Sterne Parent @rrrcsl EDWVARDW'. BRIGGS, OhBROOKLYN, AND JOHN DuWALTON, OF NEYV YonK, n; Y.

PUNCH.

SPECIFIGA'IIQN forming part of Letters Patent No. 295,227, dated March18, 1884.

ness, may be operated with less power, lessliar bility to crack orinjure the material, and departure from the size and shape of the punchthan has been found practicablewith punches of the ordinary kind andcharacter, and also one which wilhitself belessliableto injuryin otherwords, more durable when subjected to the stress of actual use undersevere conditions.

For this purpose punches have been made with a supplementalcuttingshoulder produced by reducing the diameter of what would 2otherwise be the acting end of the punch by turning the same down toform a sharp circumferential edge on the fiat face of aperfectly-cylindrical shoulder, the object being to remove the metal bycooperating successive- 3o cutting actions of the cuttingedges of asingle punch, whereby tov avoid the ragged surface or edge produced bythe tearing action of a punch having a single face cutting-edge. In suchconstruction, the face of the cutting-edge 5 of greatest diameter joinsthe cylindrical surface of the cutting-edge of least diameter with asharp angle, so that the action of bothcutting-edges upon the metal-isalike. Punches have also been made with a cylindrical body 0 surroundedby aseeond cutting-edge of undulating or scalloped form, so that inreaming the metal around thepunched hole the shearing thereof will beborne equally by the downward projections otsaid second cutting-edge. 5Our improvement comprises a punch having successive punching-edgesformed on fiat faces of unequal diameter,and joining each other by anoutwardly inclined or curved wall, in order that the cutting-edge ofleast diameter will operate not only to remove the central por-Application filed March 30, 1883. (No model.)

tion of the material from the space to be punched, but also operate tobend the remaining portion of the metal to be removed, and thereby tocrack and break away the hard scale from the surface of such remainingportion of the metal, and thus expose the soft or unsealed surface tothe action of the succeeding cuttingedge, which determines the size ofthe hole, and which is thereby caused to cut with much less resistanceand to produce asmoother edge around the hole. In this importantparticular the first acting cutting-edge of least diameter operates in adifferent manner from the finishing cutting-edge, and gives an advantagenot hitherto attained by punches having successi ve cuttingedges. Aconical projection is formed upon the face of the cutting part of leastdiameter, and its relation to such cuttingedge is such as to bend themetal before re ceiving the action of said cutting-edge, so as 7a tobreak thescale and render the cutting easier, while at the same timesuch projection serves the function of the center holding-point commonin punches for punching metal.

' Figure 1 is aside view of a punch en1bracing one portion of my saidinvention. Eig. 2 is aside view; Fig. 3, a longitudinal sectional View,and Fig. 4 a face view, of apunch, embracing' also an additional featureof my said invention.

A isthe cylindrical body of the punch, which said body need not dili'ermaterially from that of punches in common use, and is provided with orconstructed for the use of any suitable means of attaching it to themovablehead 8 5 of a punchingpress. It is of conrse'to be understoodthat the punch is to be used in connection with a suitable bench orsupport for holding the material to be punched, and furnished with asuitable die for acting in con- 0, junction with the punch during theoperation of the latter. As this support, die, the, may be of anyordinary kind or character and designed to act in the ordinary manner inrelation to the punch, such support, die, 850., need 5 not be herespecifically described. The face, however, of the punch is of novelconstruction, being provided with successive puncl1- ing-edgest\vo ormore, joined by a curved wall which act in succession upon the ma- 10oterial to be punched. so that the latter offers less resistance at anyone moment of time during the operation of punching than is possiblewhere a single cu tting-edge is required to at once part the materialaround the whole circumference of the holeor opening to be made.Furthermore, the punch constructed according to my said invention, withthe curved wall intervening bet-ween the cutting-edges,

when operating on iron, rolled steel, and the like,loosensthe scaleupon'the surfaceofthematerial and causes the same to chip or scale off,leaving the naked and comparatively soft metal exposed to the action ofthe larger or circumferential cutting-edge of the punch, thereby greatlylessening the power required to drive the said edge through thematerial.

As represented in Fig. 1, the face of the punch is formed with a centralprojecting portion of less diameter than the face of the punch itself,this portion having a cutting-edge, a, which should be substantiallyconcentric with the circumferential cutting-edge b of the punch, andjoin it by a curved wall, 6, as shown. WVhen the punch is forced againstthe material to be punched, the edge a acts first, and not only removesa central portion of the material from the space to be punched, but alsocracks and breaks away the hard scale from the surrounding portions. Thecutter, being deprived of support from the central portion, now removed,of the material, and also exposing its naked or unsealed surface,affords much less resistance to the succeeding action of the edge I),which determines the size of the hole.

Furthermore, owin to this diminished resistenlargement does not exceedone-eighthof an inch. advantageous operation of my said invention, Iprovide atthe center of the part A a projecting conical teat orprojection, c, which, by bending the material into a conical cavity atthe center of the part to be punched out, bends said material at suchportions into such position thatitmay be mostadvantageously sheared bythe successive action of the edges a and b. When desired, the face ofthe punch may be provided with more than one additional cut-' ting-edgea, arranged within its circumferential cutting-edge b.

It will be seen that the conical projection c not only serves thepurpose of the holdingpoint common in flat-faced punches, but has suchrelation to the cutting-edges of least diameter as to prepare the metalto receive the first out by bending it into a conical cavity at thecenter part to be punched, and thus serve to break the surface scale andrendtrcessive annular punching-edges a 12, joined byan outwardlyinclined or curved wall, e, as described, for the purpose set forth.

2. The metal-punch herein shown and described, having the successiveannular punching-edges a 12, joined by a curved wall, 6, and a coneprojection, 0, having the described re- In order to obtain, however, themost lation to the cutting-edge of least diameter,

for the purposes specified.

EDWVARD W. BRIGGS. JOHN D. WVALTON.

Witnesses:

RUDoLF H. BJELLMAN, EDWARD A. HoLLEY.

